Tool for adjusting contact springs



April 2, 1968 r A. N. A. LUSSIER 3,375,696 v TOOL FOR ADJUSTING CONTACTSPRINGS Filed Jan. 7, 1966 INVENTOR A. N. A. LUSSIER BY JW PATENT AGENTSUnited States Patent 3,375,696 TOOL FOR ADJUSTING CONTACT SPRINGSAntoine N. Andre Lussier, Chambly, Quebec, Canada, assignor to NorthernElectric Company Limited, Montreal, Quebec, Canada Filed Jan. 7, 1966,Ser. No. 519,317 7 Claims. (Cl. 72400) This invention relates to a toolfor adjusting resilient contact spring-s.

Contact springs are widely used in .the electrical industry. They areused extensively in the telephone field and more particularly instep-by-step switches. Such switches are mounted on shelves andelectrical connection is achieved by the use of plugs adapted to engagethe contact springs. Specifically, the plugs are inserted between pairsof contact springs, and because certain pairs of springs must makecontact when the plugs are removed, the springs must be tensionedagainst each other. Furthermore, the springs must be so aligned that theassociated plug will enter between them without snagging on the tips ofthe springs. At present, the pairs of springs are adjusted by hand withtwo pairs of pliers used simultaneously. The fixed portion of a pair ofcontact springs is grasped and held stationary with one pair of plierswhile the contact portion of one spring is adjusted toward its mate withthe other pair of pliers. The mating contact spring is adjusted in thesame manner so that when adjustrnent is complete the point of contact ofthe two springs will be aligned with a point midway between the fixedends of the springs.

There is a substantial amount of guesswork in this adjustment procedurewith the result that the pressure between the contacts is ofteninadequate and furthermore that the springs are not always perfectlyaligned.

The disadvantages of the prior art are overcome in accordance with thepresent invention by providing a plierlike tool for adjusting a pair ofspaced resilient contact springs fixed at one end and having portionsmovable into contact with each other usually adjacent free ends of thesprings. The tool comprises a pair of elongated members pivotallyconnected together intermediate their ends to form a pair of handles anda pair of jaws for embracing and deforming the springs into contact witheach other. An anvil is pivotally connected to the elongated member andcomprises spacing means in the form of a member which is offset from theplane of the jaws and adapted to be inserted between the contact springsintermediate the fixed ends and the movable portions. The anvil furthercomprises means for centering the spacing member between the jaws whenthe jaws are closed, and means for aligning the spacing member with themidpoint between the fixed ends of the springs. The novel anviltherefore ensures that the cont-act springs will always be deformed in aposition such that the point of contact between the two movable ends ofthe springs are aligned with a point midway between the fixed ends ofthe springs.

With the above tool the adjustment is done in only one operation and allthe guesswork to determine the pressure between the contacts iseliminated. The accuracy, quality and uniformity of adjustment isimproved and also the time for adjustment is greatly reduced.

The invention will now be described with reference to a preferredembodiment of the invention in which:

FIGURE 1 illustrates a tool, in accordance with the invention, inposition for adjusting the contact springs;

FIGURE 2 illustrates a number of contact springs mounted on a support,the center one being normally closed; 7

FIGURE 3 illustrates a plan view of the adjusting tool;

FIGURE 4 illustrates a side view of the adjusting tool;

FIGURE 5 illustrates a section view along line 5-5 in FIGURE 4illustrating the .anvil and the spacing member in position beforeclosure of the jaws on the contact springs;

FIGURE 6 illustrates the same section view as FIG- URE 5 after closureof the jaws.

FiGURES 1 and 2 illustrate a support m which are mounted a number ofpairs of contact springs 11, 12 and 13 each having two contact springs14 and 15 fixed at one end and separated by an insulator 16. Plugs (notshown) are adapted to be inserted between the movable ends of springs 14and 15. As mentioned previously certain springs are required to makecontact when the plugs are removed. This is exemplified in FIGURE 2 byswitch 12 which is shown normally closed. Consequently the contactsprings have to be .adjusted to make contact and the present inventionis concerned with a tool generally shown in FIGURE 1 for effecting suchadjustment.

Referring .now to FIGURES 3 and 4, "the contact adjusting tool of thepresent invention comprises a pair of elongated members 17 and 18pivotally connected by a bolt 19 to form a pair of handles 20 and] 21and a pair of jaws 22 and 23. An anvil 24 is pivotally connected to theelongated members by the bolt 19. Anvil 24 comprises a spacing member 25which is offset from the plane of the jaws 22 and 23 and adapted. to beinserted between contact springs 14 and 15. Spacing member 25 ispositioned in a slot 26 in the center of the top surface of anvil 24 andsecured to the anvil by means of a screw 27 which protrudes through theanvil from the bottom surface thereof. Spacing member 25 has a pointedend 28 to facilitate entry between the contact springs. It is understoodhowever, that spacing member 25 may be otherwise secured to anvil 24 andmay even be integral therewith.

Screw 27 is provided with a smooth elongated extension 29 in the form ofa pin which extends between jaws 22 and 23 to act as a centering meansfor centering spacing member 25 between the jaws. Centering means 29 maytake various forms and it is only as a matter of convenience that it isshown as an extension of screw 27.

Pin 29 is also used to limit the amount of closure of the jaws tocontrol the pressure of the jaws on the contact springs. By varying thesize of the pin various amount of closure of the jaws may be obtained.The jaws 22 and 23 also have slots 30 to permit full closure of the jawswhen it is required with a minimum size screw.

Anvil 24 has a projection 31 which acts as a means for aligning thespacing member 25 with the midpoint between the fixed ends of thesprings. Projection 3'1 has a recess portion 32 wide enough to receivethe fixed ends of the contact springs. The sides of the recess 31 may besloped outwardly approximately 5 degrees to facilitate entry of thesprings therein.

Also shown in FIGURES 3 and 4 of the drawings is a pin 33 mounted on theanvil 24 and siidable to a position with one end between the open jaws22 and 23 to maintain the anvil centrally located between the jaws whenthe latter are open. Pin 33 protrudes through the anvil 24 and is biasedin position by a spring 34 secured under the fastening nut of bolt 19.The end of the pin which lies between the open jaws is cone shaped suchthat the jaws engage said cone shaped end on closing to urge the pin outof its position between the jaws.

It is to be understood equivalent means may be used to perform thefunctions of each of the elements of the tool disclosed. A preferredembodiment has been described by way of illustration only and applicantdoes not intend to be limited by such description.

The operation of the adjusting tool is shown schematically in FIGURES 5and 6. As shown in FIGURE 5, the fixed ends of the contact springs areplaced in groove 32 of anvil 24 and spacing member 25 is inserted be-When the jaws are fully closed about pin 29, the point of contact of themating springs will be in alignment with the midpoint between the fixedends because the aligning means 31 provides for proper alignment of thespacing member 25 and centering means 29 with the midpoint between thefixed ends of the springs.

It is seen therefore, that with the above described adjusting tool theoperation is performed in only one move and that all guesswork todetermine the amount of deformation of the springs, the pressure betweenthe contact springs and the alignment of the springs is eliminated. Theaccuracy, quality and uniformity of adjustment is greatly improved andalso the time required for adjusting the springs is greatly reduced.

What is claimed is:

1. A plier-like tool for adjusting a pair of spaced resilient contactsprings fixed at one end and having portions movable toward each other,said tool comprising a pair of elongated members pivotally connectedtogether intermediate their ends to form a pair of handles and a pair ofjaws for embracing and deforming said movable portions of the springsinto contact with each other, and an anvil pivotally connected to saidmembers, said anvil including spacing means offset from the plane of thejaws for insertion between the contact springs intermediate the fixedends and said movable portions, centering means rigidly connected to theanvil for centering the spacing means between the jaws when the jaws areclosed, and aligning means rigidly connected to the anvil and adapted toengage the fixed ends of the contact springs for aligning the spacingmeans with the midpoint between the fixed ends whereby the movableportions are deformed into contact in alignment with said midpoint.

2. A tool as defined in claim 1 wherein the pivotal connection of theanvil to said members coincides with the pivotal connection between saidmembers.

3. A tool as defined in claim 2 including means for positioning theanvil between the jaws when the latter are open.

4. A tool as defined in claim 3 wherein said positioning means comprisesa pin mounted on the anvil and slidable to a position with one endbetween the open jaws, spring means biasing the pin to said position,said one end of the pin being substantially cone-shaped such that thejaws engage said one end on closing to urge the pin from said positionbetween the jaws.

5. A tool as defined in claim 1 including means for limiting thedistance between the jaws when the latter are closed to control thepressure of the jaws on the contact springs.

6. A tool as defined in claim 5 wherein said limiting means comprises aportion of said centering means projecting between the jaws.

7. A tool as defined in claim 1 wherein said aligning means comprises aprojection of said anvil having a recess therein for receiving the fixedends of the contact springs.

References Cited UNITED STATES PATENTS 2,810,312 10/1957 Mueller '72409RICHARD J. HERBST, Primary Examiner.

R. D. GREFE, Examiner.

1. A PLIER-LIKE TOOL FOR ADJUSTING A PAIR OF SPACED RESILIENT CONTACTSPRINGS FIXED AT ONE END AND HAVING PORTIONS MOVABLE TOWARD EACH OTHER,SAID TOOL COMPRISING A PAIR OF ELONGATED MEMBERS PIVOTALLY CONNECTEDTOGETHER INTERMEDIATE THEIR ENDS TO FORM A PAIR OF HANDLES AND A PAIR OFJAWS FOR EMBRACING AND DEFORMING SAID MOVABLE PORTIONS OF THE SPRINGSINTO CONTACT WITH EACH OTHER, AND AN ANVIL PIVOTALLY CONNECTED TO SAIDMEMBERS, SAID ANVIL INCLUDING SPACING MEANS OFFSET FROM THE PLANE OF THEJAWS FOR INSERTION BETWEEN THE CONTACT SPRINGS INTERMEDIATE THE FIXEDENDS AND SAID MOVABLE PORTIONS, CENTERING MEANS RIGIDLY CONNECTED TO THEANVIL FOR CENTERING THE SPACING MEANS BETWEEN THE JAWS WHEN THE JAWS ARECLOSED, AND ALIGNING MEANS RIGIDLY CONNECTED TO THE ANVIL AND ADAPTED TOENGAGE THE FIXED ENDS OF THE CONTACT SPRINGS FOR ALIGNING THE SPACINGMEANS WITH THE MIDPOINT BETWEEN THE FIXED ENDS WHEREBY THE MOVABLEPORTIONS ARE DEFORMED INTO CONTACT IN ALIGNMENT WITH SAID MIDPOINT.